scholarly journals Carbon-Based Quantum Dots for Electrochemical Detection of Monoamine Neurotransmitters—Review

Biosensors ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 162
Author(s):  
Saheed E. Elugoke ◽  
Abolanle S. Adekunle ◽  
Omolola E. Fayemi ◽  
Bhekie B. Mamba ◽  
El-Sayed M. Sherif ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electrochemical Sensors ◽  
Graphene Quantum Dots ◽  
Good Sensitivity ◽  
Health Issues ◽  
Monoamine Neurotransmitters ◽  
Good Electrocatalytic Activity ◽  
Low Cytotoxicity ◽  
Made In ◽  
Carbon Based

Imbalance in the levels of monoamine neurotransmitters have manifested in severe health issues. Electrochemical sensors have been designed for their determination, with good sensitivity recorded. Carbon-based quantum dots have proven to be an important component of electrochemical sensors due to their high conductivity, low cytotoxicity and opto-electronic properties. The quest for more sensitive electrodes with cheaper materials led to the development of electrochemical sensors based on carbon-based quantum dots for the detection of neurotransmitters. The importance of monoamine neurotransmitters (NTs) and the good electrocatalytic activity of carbon and graphene quantum dots (CQDs and GQDs) make the review of the efforts made in the design of such sensors for monoamine NTs of huge necessity. The differences and the similarities between these two quantum dots are highlighted prior to a discussion of their application in electrochemical sensors over the last ten years. Compared to other monoamine NTs, dopamine (DA) was the most studied with GQDs and CQD-based electrochemical sensors.

scholarly journals Carbon Based Nanodots in Early Diagnosis of Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Gurpal Singh ◽  
Harinder Kaur ◽  
Akanksha Sharma ◽  
Joga Singh ◽  
Hema Kumari Alajangi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Early Stage ◽  
Imaging Techniques ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Diagnostic Methods ◽  
Early Diagnosis Of Cancer ◽  
Successful Treatment Outcome ◽  
Wide Range ◽  
Carbon Based

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

scholarly journals One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 104 ◽  
Author(s):  
Rabeb El-Hnayn ◽  
Laetitia Canabady-Rochelle ◽  
Christophe Desmarets ◽  
Lavinia Balan ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Colloidal Stability ◽  
Antioxidant Activities ◽  
Graphene Quantum Dots ◽  
Average Diameter ◽  
Functionalized Graphene ◽  
One Step ◽  
Low Cytotoxicity ◽  
Health Applications

2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.

Recent Advances in the Cancer Bioimaging with Graphene Quantum Dots

2018 ◽  
Vol 25 (25) ◽  
pp. 2876-2893 ◽  
Author(s):  
Keheng Li ◽  
Xinna Zhao ◽  
Gang Wei ◽  
Zhiqiang Su
Keyword(s):  
Quantum Dots ◽  
Biomedical Applications ◽  
Cell Imaging ◽  
Graphene Quantum Dots ◽  
Biological Properties ◽  
Live Cells ◽  
Physical Chemical ◽  
Specific Cancer ◽  
Good Biocompatibility ◽  
Low Cytotoxicity

Fluorescent graphene quantum dots (GQDs) have attracted increasing interest in cancer bioimaging due to their stable photoluminescence (PL), high stability, low cytotoxicity, and good biocompatibility. In this review, we present the synthesis and chemical modification of GQDs firstly, and then introduce their unique physical, chemical, and biological properties like the absorption, PL, and cytotoxicity of GQDs. Finally and most importantly, the recent applications of GQDs in cancer bioimaging are demonstrated in detail, in which we focus on the biofunctionalization of GQDs for specific cancer cell imaging and real-time molecular imaging in live cells. We expect this work would provide valuable guides on the synthesis and modification of GQDs with adjustable properties for various biomedical applications in the future.

scholarly journals Application of Electrochemical Sensors Based on Carbon Nanomaterials for Detection of Flavonoids

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2020
Author(s):  
Jinchun Hu ◽  
Zhenguo Zhang
Keyword(s):  
Carbon Nanomaterials ◽  
Electrochemical Sensors ◽  
Graphene Quantum Dots ◽  
High Sensitivity ◽  
Research Field ◽  
Electrochemical Sensing ◽  
Detection Methods ◽  
Health Issues ◽  
Fast Detection ◽  
Anti Cancer

Flavonoids have a variety of physiological activities such as anti-free radicals, regulating hormone levels, antibacterial factors, and anti-cancer factors, which are widely present in edible and medicinal plants. Real-time detection of flavonoids is a key step in the quality control of diverse matrices closely related to social, economic, and health issues. Traditional detection methods are time-consuming and require expensive equipment and complicated working conditions. Therefore, electrochemical sensors with high sensitivity and fast detection speed have aroused extensive research interest. Carbon nanomaterials are preferred material in improving the performance of electrochemical sensing. In this paper, we review the progress of electrochemical sensors based on carbon nanomaterials including carbon nanotubes, graphene, carbon and graphene quantum dots, mesoporous carbon, and carbon black for detecting flavonoids in food and drug homologous substances in the last four years. In addition, we look forward to the prospects and challenges of this research field.

scholarly journals Graphene Quantum Dots-Based Nanocomposites Applied in Electrochemical Sensors: A Recent Survey

Electrochem ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 490-519
Author(s):  
Murilo H. M. Facure ◽  
Rodrigo Schneider ◽  
Jessica B. S. Lima ◽  
Luiza A. Mercante ◽  
Daniel S. Correa
Keyword(s):  
Quantum Dots ◽  
Molecularly Imprinted Polymers ◽  
Electrochemical Sensors ◽  
Graphene Quantum Dots ◽  
Electrochemical Sensing ◽  
Synthesis Methods ◽  
Current Trends ◽  
Sensing Platforms ◽  
Metal Organic ◽  
2D Nanomaterials

Graphene quantum dots (GQDs) have been widely investigated in recent years due to their outstanding physicochemical properties. Their remarkable characteristics allied to their capability of being easily synthesized and combined with other materials have allowed their use as electrochemical sensing platforms. In this work, we survey recent applications of GQDs-based nanocomposites in electrochemical sensors and biosensors. Firstly, the main characteristics and synthesis methods of GQDs are addressed. Next, the strategies generally used to obtain the GQDs nanocomposites are discussed. Emphasis is given on the applications of GQDs combined with distinct 0D, 1D, 2D nanomaterials, metal-organic frameworks (MOFs), molecularly imprinted polymers (MIPs), ionic liquids, as well as other types of materials, in varied electrochemical sensors and biosensors for detecting analytes of environmental, medical, and agricultural interest. We also discuss the current trends and challenges towards real applications of GQDs in electrochemical sensors.

Graphene quantum dots for the inhibition of β amyloid aggregation

Nanoscale ◽  
2015 ◽  
Vol 7 (45) ◽  
pp. 19060-19065 ◽  
Author(s):  
Yibiao Liu ◽  
Li-Ping Xu ◽  
Wenhao Dai ◽  
Haifeng Dong ◽  
Yongqiang Wen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Amyloid Aggregation ◽  
Aβ Peptides ◽  
Β Amyloid ◽  
Low Cytotoxicity

GQDs, efficient and low-cytotoxicity inhibitors, are reported for their application in inhibiting the aggregation of Aβ peptides.

High-Purity Amino-Functionalized Graphene Quantum Dots Derived from Graphene Hydrogel

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650138 ◽  
Author(s):  
Yinhua Jin ◽  
Hongyi Qin ◽  
Jang Ah Kim ◽  
Sun-Young Kim ◽  
Hyeong-U Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Purity ◽  
Hydrothermal Reaction ◽  
Graphene Quantum Dots ◽  
Synthesis Method ◽  
Water Soluble ◽  
Synthesis Process ◽  
Functionalized Graphene ◽  
Ultrasonic Probe ◽  
Low Cytotoxicity

The unique properties of graphene quantum dots (GQDs) make them interesting candidate materials for innovative applications. Herein, we report a facile method to synthesize amino-functionalized graphene quantum dots (AF-GQDs) by a hydrothermal reaction. Graphene oxide (GO) was synthesized by Hummer’s method where ultra-small GO sheets were obtained by a prolonged oxidation process followed by sonication using an ultrasonic probe. Subsequently, graphene hydrogel (GH) was also obtained by a hydrothermal synthesis method. Proper care was taken during synthesis to avoid contamination from water soluble impurities, which are present in the precursor, GO solution. Following the treatment of GH in ammonia, ultra-small amino-functionalized graphene fragments (AF-GQDs) were formed, which detached from the GH to eventually disperse evenly in the water without agglomerating. This modified synthesis process enables the formation of high-purity AF-GQDs (99.14%) while avoiding time-consuming synthesis procedures. Our finding shows that AF-GQDs with sizes less than 5[Formula: see text]nm were well dispersed. A strong photoluminescence (PL) emission at [Formula: see text]410[Formula: see text]nm with 10% PL quantum yield was also observed. These AF-GQDs can be used in many bio applications in view of their low cytotoxicity and strong fluorescence that can be applied to cell imaging.

scholarly journals Rapid synthesis of graphene quantum dots using a continuous hydrothermal flow synthesis approach

RSC Advances ◽  
2017 ◽  
Vol 7 (24) ◽  
pp. 14716-14720 ◽  
Author(s):  
Suela Kellici ◽  
John Acord ◽  
Nicholas P. Power ◽  
David J. Morgan ◽  
Paolo Coppo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Environmentally Benign ◽  
Rapid Synthesis ◽  
Flow Synthesis ◽  
Benign Synthesis ◽  
Low Cytotoxicity ◽  
Green Fluorescent ◽  
Synthesis Approach ◽  
Hydrothermal Flow

A rapid and environmentally benign synthesis of green fluorescent graphene quantum dots (GQD) with low cytotoxicity via Continuous Hydrothermal Flow Synthesis (CHFS) aided by calix[4]arene tetrasulfonic acid (SCX4) as a particle size limiting agent.

scholarly journals Carbon-based quantum particles: an electroanalytical and biomedical perspective

2019 ◽  
Vol 48 (15) ◽  
pp. 4281-4316 ◽  
Author(s):  
Khadijeh Nekoueian ◽  
Mandana Amiri ◽  
Mika Sillanpää ◽  
Frank Marken ◽  
Rabah Boukherroub ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Confinement Effect ◽  
Spherical Carbon ◽  
Quantum Particles ◽  
Carbon Based

Carbon-based quantum particles, especially spherical carbon quantum dots (CQDs) and nanosheets like graphene quantum dots (GQDs), are an emerging class of quantum dots with unique properties owing to their quantum confinement effect.

Graphene Quantum Dots in Electrochemical Sensors/Biosensors

2019 ◽  
Vol 15 (2) ◽  
pp. 103-123 ◽  
Author(s):  
Farnoush Faridbod ◽  
Afsaneh L. Sanati
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Electrochemical Properties ◽  
Edge Effects ◽  
Quantum Confinement ◽  
Electrochemical Sensors ◽  
Graphene Quantum Dots ◽  
Graphene Oxides ◽  
Reduced Graphene ◽  
Fluorescent Nanomaterials

Background: Graphene and its derivatives, as most promising carbonic nanomaterials have been widely used in design and making electrochemical sensors and biosensors. Graphene quantum dots are one of the members of this family which have been mostly known as fluorescent nanomaterials and found extensive applications due to their remarkable optical properties. Quantum confinement and edge effects in their structures also cause extraordinary electrochemical properties. Objective: Recently, graphene quantum dots besides graphene oxides and reduced graphene oxides have been applied for modification of the electrodes too and exposed notable effects in electrochemical responses. Here, we are going to consider these significant effects through reviewing some of the recent published works.

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